水浸束缚应激大鼠胃壁细胞形态和泌酸功能的研究

背景:应激性溃疡(SU)是临床危重疾病的常见并发症,通常认为胃黏膜缺血是SU的主要发病机制,而胃酸则在此基础上起重要作用,但胃酸在SU发病中的确切作用尚未完全阐明.目的:研究水浸束缚应激(WRS)大鼠胃壁细胞形态和泌酸功能的变化,以进一步阐明胃酸在SU发病中的作用.方法:将15只Sprague-Dawley大鼠随机分为WRS2 h组、WRS 4 h组和正常对照组,予相应处理后测定胃液pH值,处死大鼠,评估胃黏膜溃疡指数(UI),以免疫荧光技术标记H /K -ATP酶后用激光共聚焦扫描显微镜观察壁细胞形态并进行分类和计数.分析胃液pH值与胃黏膜UI和分泌期壁细胞数之间的关系.结果:WRS 2 h组和WRS 4 h组的胃液pH值均较正常对照组显著降低(P＜0.01),两组WRS组之间则无显著差异.WRS 2 h组和WRS 4 h组的胃黏膜UI和分泌期壁细胞(网格样细胞)数均显著高于正常对照组(P＜0.01),其中WRS 4 h组显著高于WRS 2 h组(P＜0.01).正常对照组的胃液pH值与分泌期壁细胞数呈负相关(r＝-0.81,P＜0.05),WRS组的胃液pH值与胃黏膜UI和分泌期壁细胞数均呈负相关(r=-0.85,P＜0.05;r=-0.89,P＜0.05).结论:WRS大鼠的胃酸分泌与胃黏膜UI和分泌期壁细胞数呈正相关,从细胞学水平证明胃酸增高在SU的形成中起重要作用.

Study on Morphology and Acid Secretion of Gastric Parietal Cells in Rats with Water-immersion Restraint Stress

Background: Stress ulcer (SU) is one of the common complications in critically ill patients. The presence of gastric luminal acid is essential for the development of SU on the basis of gastric ischemia, but the precise role of gastic acid in SU remains unclear. Aims: To study the changes of gastric parietal cellular morphology and acid secretion in rats with water-immersion restraint stress (WRS) and to elucidate further the role of acid in the pathogenesis of SU. Methods: Fifteen Sprague-Dawley rats were randomly divided into 3 groups: WRS 2 h group, WRS 4 h group and normal controls. The gastric pH value was measured after model construction, and then all animals were sacrificed. The gastric ulcer index (UI) was evaluated by the score system. Fluoroimmunoassay of gastric parietal cells by combining its H /K -ATPase with special antibodies was used and the parietal cells were observed, categorized and counted by confocal laser scanning microscope. A linear correlation analysis was performed to determine the relevance of gastric pH value, gastric UI, and the number of secreting parietal cells. Results: The gastric pH value of rats in WRS 2 h and WRS 4 h groups was significantly lower than that of the normal controls (P<0.01), no difference was found between the two WRS groups. The gastric UI of rats in WRS groups was significantly higher than that of the normal controls (P<0.01), and that of rats in WRS 4 h group was much higher than that of rats in WRS 2 h group (P<0.01). Similar changes could be observed in the number of secreting parietal cells (reticular pattern) among the three groups. In intact rats, the gastric pH value was negatively correlated with the number of secreting parietal cells (r=-0.81, P<0.05); and the gastric pH value was also negatively correlated with both gastric UI (r=-0.85, P<0.05) and the number of secreting parietal cells (r=-0.89, P<0.05) in WRS rats. Conclusions: The acid secretion in WRS rats are positively correlated with the gastric UI and the number of secreting parietal cells, which confirm the key role of acid in the development of SU at cytological level.